Ten years ago, her livelihood was all contained in a battered, aluminum-sided food truck, like the one she has parked in the lot in front of her Langley Park businesses. Even after she moved into a storefront, she continued to serve savory beef sandwiches, taquitas, pupusas and pickled cabbage from the truck. For patrons who want to sit for a moment to sip frosty cans of sweet licuados, similar to smoothies, and enjoy their meals, she carved out a small outdoor cafe next to the building.

Each new enterprise diversified and buffered her livelihood from the growing competition in surrounding neighborhoods, where dozens of food trucks, known as vendadores by the many Latinos who operate and patronize them, have cropped up since Escobar began.

Most of the four-wheeled operations are illegal; Prince George's County does not license mobile food vendors except for special events like fairs or festivals. Police have rousted them periodically, and now a new crackdown is beginning in earnest.

Many of the Latino merchants are divided over who should be targeted -- everyone or just the newcomers.

Last week, county health regulators began fanning out to issue warnings that the operators are violating parking, health or zoning laws and must shut down. Five officers visited Escobar's business over the weekend and told her the truck violated county laws. They left with her a warning, printed on red paper, stating in part "This Final Notice is to advise you that you have been observed again engaging in illegal vending activities, and you must stop this activity immediately." A logo read: "Prince George's County: Part of a Growing Renaissance."

If she failed to comply, the officers said, they would return and arrest the workers serving food from the truck, and they might impound the vehicle. On Monday, a health department inspector returned to shut down her outdoor cafe.

Until now, Escobar believed that she was operating her businesses legally. Her truck has a certificate of inspection from the county health department, which she updates every year. It is parked on the lot of the building where she pays rent, so she assumes she is not violating parking regulations, she said.

Yet she and others have received dozens of $500 parking tickets recently from county police.

More than a decade ago, the Prince George's Council ordered a halt to street sales of barbeque, crabs, pupusas and other foods from vending trucks. But the operations never really disappeared, in part because of legal challenges and confusion over the law. These days, business is again booming as a new wave of trucks has taken to county roads.

Escobar, who came to the United States from El Salvador 17 years ago and began her first truck business as an earlier mobile vending ban was being challenged in court, does not begrudge the new operators who are trying to build their financial futures, plateful by plateful.